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Valsir S.p.a
Waste and water
supply systems, underfloor heating system
and flush cisterns


Pexal and Mixal: The ideal pipe for radiant systems.

Pexal e Mixal, i tubi ideali per i sistemi radianti

Heat performance

The presence of the aluminium layer, its thickness and position, result in excellent heat conductivity characteristics.

With Pexal® and Mixal® pipes it is possible to carry out floor heating systems with higher heat outputs.

In fact the greater conductance generates higher temperatures on the pipe surface as compared with all-plastic pipes (PE-X and PERT) and this advantage is reflected, for example in the possibility of obtaining relatively low supply temperatures.

The greater performance of Pexal® and Mixal® pipes compared with all-plastic pipes means greater system output at equal flow conditions. An example: the 16x2 Mixal® pipe has the same thermal output as the 17x2 PE-X pipe.

Mechanical behaviour

The mechanical characteristics of the Pexal® and Mixal® pipes make them ideal for use in floor heating systems. The bending radius corresponds to 2.5 times the pipe diameter and the circular section at the bend remains constant.

The pipe, once bent, remains in the desired position like a metal pipe; hence the use of anchor clips is not required as with all-plastic pipes.

Barrier against oxygen and UV rays

Pexal e Mixal: barriera ai raggi UV

The inner layer in aluminium acts as a perfect barrier against the passage of gaseous molecules thus avoiding the danger of corrosion due to oxygen infiltration and damage caused by exposure to UV rays

The table shows a comparison of the oxygen transmission coefficients (Oxygen Transmission Rate) of aluminium, of EVOH (the material used as an oxygen barrier in all-plastic pipes) and of crosslinked polyethylene (PE-X).

Many PEX pipes sold today are manufactured with the oxygen barrier on the outside of the pipe.

This layer is hence notably exposed, not only to superficial damages, but also to the negative effect of humidity, which drastically increases the porosity of the pipe.

Material Oxygen transmission
coefficient OTR
at 25°C and 0%
Aluminium 0
barrier EVOH 0,21
PE-X 12.000


Valsir provides complete support both during the planning phase and on site, thanks to a first-class technical office made up of a team of highly experienced engineers, capable of dealing with the most complex system requirements.

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